I wouldn't say there is much between them. I think aesthetically the K90 looks a bit better, the backlight is better as the punctuation marks on the number keys light up whereas they don't on the black widow and you don't have that god awful tribal mark staring back at you.

It feels a bit comfier as well. I'm no touch typist but my fingers seem to hit the keys better on this board than the Razer one. Whether this is down to the spacing of the keys and my large hands, I'm not sure.

There are bag loads of macro keys if you're into that sort of thing, but the software for programming them is a a bit shonky and over complicated imho.

I was sorry to see the Razer keyboard go if I'm honest. If they had more in stock when I returned it I would have had another in a heartbeat. The Corsair K90 was pretty much the only other other board they had in a similar price bracket and I had read good things about them, so after having a play around with one I decided to go with it and have loved it since.